Apparatus for training bomb aimers



April 4,- 1944. A. P. GLENNY APPARATUS FOR TRAINING BOMB AIMERS 1942 2 Sheets-Shet 1 Filed Dec. 15

FIG. I.

a! CONSTANT SPEfD J QM iHRiHiF mi-ha INVENTOR ARTHUR H GLENNY HIS ATTORNEY April 4, 1944. LE 2,345,744

APPARATUS FOR TRAINING BOMB AIMERS Filed Dec. 15, 1942 2 Sheets-Sheet 2 FIG. 2.

6 co/wrA/vrspfw Mara/Q INVENTOR ARTHUR F! GLENNY HIS ATTORNEY Patented Apr. 4, 1944 ArrAItATos role TRAINING noMB AIMERS Arthur Philip Glenny, Amberley, England, assignor to The Sperry Gyroscope Company, Limited, Brentford, England, a British company Application December 15, 1942, Serial No. 469,131 In Great Britain September 6, 1941 9 Claims.

This invention relates to improvements in apparatus for use on the ground for training bomb aimers in the operation of aircraft bomb-sights. Such apparatus should enable the bomb aimer operating the sight to be trained to carry out those operations that he would carry out during an actual approach to a target to be bombed, and for this reason, the henomena seen through the sight, and the eiiect or" these phenomena of operations effected by the bomb aimer, should closely simulate those occurring in actual flight. The invention is mainly concerned with means for simulating in a novel manner the eiiects of side winds and the manoeuvres made during a bombing attack in the presence of side winds.

According to the present invention a training apparatus is provided in which a turnable elevated sighting device such as a bomb sight is situated above a target track along which a miniature target is caused to move to approach the sight at a substantially constant speed, thus simulating the relative velocity of an aircraft and a target to be bombed; motive means are also provided which, when suitably energised, cause a continuous lateral displacement of the target, e. g., by causing the track, or at least the end of the track remote from the sight to be displaced laterally, and control means are further provided to reduce the rate at which said lateral displacement takes place, said control means being operated from a manual controller, such as a control knob, provided for controlling the turning of the line of sight. In this way the manner in which the direction of the target from the sight appears to alter is dependenton the manner in which the sight is controlled in azimuth. Preferably the line of sight is itself turned by continuously operating motive means, and the same manual controller, e. g., a control knob, adjusts the rate of turn of the line of sight and simultaneously alter the rate of turn of the target about the sight.

The invention can be carried out in a number of ways. In one embodiment the eiiect of side wind is simulated by causing motive means to set the target track turning bodily about a vertical axis through the sight, and the manual controller, in the form of a control knob, simultaneously sets a device that controls the rate of turn of the sight and also sets a device that reduces the rate of turn of the track by an amount substantially proportional to the rate of turn of the sight.

In a practical embodiment the sight is controlled by a continuously variable speed gear,

the driving member of which is driven by a constant speed motor, and the intermediate member of which is set by the azimuth rate control knob of the sight. The track may be turned about the sight by an electric motor controlled by a Wheatstone bridge. The instructor initially upsets the balance of two of the arms of the Wheatstone bridge thus causing the electric m0- tor to turn the target track round the sight at a constant rate. Such turning of th track simulates sufficiently well the efiect of a side wind during the beginning of an actual bombing attack. While the target track turns round the sight the bomb aimer sets his manual control knob to cause the sight to turn continuously to follow the target. In order to carry the invention into effect this controller is connected to the Wheatstone bridge so that its movement upsets the balance of the second pair of arms in the appropriate direction to restore the balance of the bridge as a whole. The speed of the electric motor is therefore reduced and the target track turns more slowly round the sight. A final condition is reached in which the bridge is substantially balanced and the target track is stationary so that the target approaches the sight along a line differing in direction from the original direction of approach. This simulates the phenomena during a bombing attack on a target wherein the course of the bombing craft is adjusted until its course defines a straight line through the target.

The invention is illustrated in the accompanying drawings in which Figure 1 is a diagram showing an arrangement of apparatus according to the invention employing two variable speed gearings and Figure 2 is a similar illustration of a slight modification employing a single variable speed gearing for operating the sight turning and traversing speed regulating mechanism.

Figure 3 is a perspective View showing the apparatus of Figure 2 in operation.

Referring first to Figure l, the reference numeral indicates a miniature target mounted on an endless band 3i arranged to be driven through suitable gearing 32 by a motor 2 so that the target can be moved continuously along the length of a board 3 or other suitable supporting base.

The board 3 is supported on a surface such as table 33 (Fig. 3) by a vertical pivot pin 4 at one end and at the other end by a floor wheel 5 which is arranged to be driven through suitable gearing 35 by an electric traversing motor 6 of a suitable variable-speed type so that the board can be made to swing laterally about the pivot pin 4 at a rate which can be varied continuously by adjustment of the supply voltage.

The sight 1 is mounted so that it can be turned about the pin 4 by gearing 9 and is governed by an azimuth rate knob Ill which controls the t ni movement of the sight indirectly through a variable speed gearing. In the arrangement shown, this variable speed gearing consists of a driving disc l2 rotated at constant speed by a suitable dIiViIlg motor 36, a driven cylinder [3 and an intermediate member comprising a ball carriage I4 containingtwo balls l-5 which roll against one another and against the disc l2 and cylinder l3. The carriage I 4 is adjustable along the radius of the disc l2 by means of a screw I 6 so that the speed of the wheel l3 can be adjusted to any value between zero and a certain finite value in either forward or reverse direction.

The knob I0 is also coupled through a flexible drive I! or other suitable mechanical transmission mechanism to the adjusting screw l8 of a variable speed gearing which may be similar to that previously described and which transmits movement from a constant speed driving disc I9 through ball carriage s1 and cylinder 38 to an adjusting screw 2&3 adapted to move a sliding electrical contact 2i along a potentiometer resistance 22. The disc I9 is driven at a constant speed by motor 39.

A second potentiometer resistance 23 equipped with a manually adjustable sliding contact 24 is connected with the resistance 22 so as to form a Wheatstone bridge having a pair of input terminals marked and in the drawings which are connected to a battery or other suitable source of current for the motor 6. The input terminals of the motor 6 are connected through suitable leads to the sliding contacts 2| and 24.

In the operation of the device, the motor 2 causes the target device I to approach the sight 'I at a substantially constant speed, thus simulating the relative velocity of an aircraft and a target to be bombed.

When the instructor adjusts the contact 24 so as to upset the balance of the Wheatstone bridge, the motor 6 runs and causes the target to be displaced laterally in simulation of the effect of drift. While the target track turns round the sight, the bomb aimer sets his manual control H] to cause the sight I to turn continuously to follow the target. This setting of the control in also causes the contact 2| to move continuously so that the speed of the motor 6 is continuously reduced at a rate dependent upon the rate of turning of the sight A. A final condition is reached in which the bridge is substantially balanced and the target track is stationary so that the target approaches the sight along a line differing in direction from the original direction of approach. This simulates the phenomena during a bombing attack on a target wherein the heading of the sighting craft is continuously varied to compensate for side wind components until its course defines a straight line through the target.

In the modification shown in Figure 2 of the drawings, the gearing 9 which imparts turning movement to the sight and the adjusting screw 20 which controls the speed of the traversing motor are both driven from the same variable speed drive I2, l5, 13 instead of being driven from two separate variable speed drives. Otherwise the arrangement is exactly the same as that described with reference to Figure 1 and the efiect is the same. Corresponding parts in Figures 1 and 2 are marked with the same reference numerals.

During an actual bombing attack the presence of side winds results in drift of the craft, and this becomes evident as an apparent lateral movement of the target as seen in the sight; the bomb aimer must therefore set the line of sight turning. It is also necessary to turn the aircraft up-wind to neutralise the drift that is taking place; and, in practice, the turning of the aircraft is carried out on the basis of the information concerning drift that is supplied by the rate at which the line of sight is being turned. The result is obtained that the drift decreases, and the apparent lateral movement of the target slows down, in a manner dependent on the rate at which the line of sight has been controlled. All this is successfully simulated by the invention, as is also the fact that the lateral displacement finally becomes zero and th rate of turn of the sight line simultaneously becomes zero solely as a result of the past operation of the azimuth rate knob in the site.

The apparatus shown in the drawings may be modified to simulate the effects of adjustments made to the sight to allow for the transverse component of the trail of the bomb. For this purpose the near end of the target track may be displaced laterally. The adjustment may be connected to be operated by a manual controller already present in the sight for tilting the sight as a whole or for otherwise tilting the normally vertical plane in which the line of sight is elevated by the elevation control of the sight.

I claim:

1. Apparatus for training bomb aimers comprising a turnable sighting device, a target device arranged to move towards the sighting device and a traversing mechanism adapted to produce a continuous lateral displacement of the track of the target device during its movement towards the sighting device, wherein the turning of the sighting device is controlled by a manually operable device which also governs the speed of the traversing mechanism so that as the sighting device is turned to follow target device the rate of lateral displacement of the track of the target device is reduced.

2. Apparatus according to claim 1 wherein the manually operable device controls the turning of the sighting device indirectly through the medium of a variable speed gearing which transmits turning movement to the sighting device from a constant speed driving member.

3. Apparatus for training bomb aimers comprising a turnable sighting device, a target device arranged to move toward said sighting device, a traversing mechanism adapted to produce a lateral displacement of the target, and a manually operable device for turning said sighting device and simultaneously governing the speed of said traversing mechanism.

4. Apparatus for training bomb aimers, comprising a turnable sighting device, a target device arranged to move toward said sighting device, a traversing mechanism adapted to produce a lateral displacement of the target, a settable variable speed device for turning said sighting device, and means responsive to the setting of said variable speed device for governing the speed of said traversing mechanism.

5. Apparatus for training bomb aimers, comprising a turnable sighting device, a target device arranged to move toward said sighting device, a traversing mechanism adapted to produce a lateral displacement of the target, a settable variable speed device for turning said sighting device, and a second variable speed device actuated by said settable variable speed device for controlling the speed of said traversing mechanism.

6. Apparatus for training bomb aimers, comprising a turnable sighting device, a target device arranged to move toward said sighting device, a traversing mechanism adapted to produce a lateral displacement of the target, a manually operable device for turning said sighting device, and means controlled by said manually operable device for governing the speed of said traversing mechanism.

7. Apparatus for training bomb aimers, comprising a turnable sighting device, a target device arranged to move toward said sighting device, a manually operable device for turning said sighting device, and a traversing mechanism controlled by said manually operable device for laterally displacing said target device.

8. Apparatus according to claim 7, wherein said traversing mechanism is driven by a variable speed drive adapted to be controlled by an instructor and said manually operable device.

9. Apparatus according to claim I, wherein said traversing mechanism is driven differentially from two variable speed devices, the speed control member of one of said devices being initially set by the instructor, and the speed control member of the other of said variable speed devices being controlled by said manually operable device.

ARTHUR PHILIP GLENNY. 

